diff --git a/object.c b/object.c
index d8d09f92aa..6b06297a5f 100644
--- a/object.c
+++ b/object.c
@@ -191,10 +191,15 @@ struct object *parse_object(const unsigned char *sha1)
 	enum object_type type;
 	int eaten;
 	const unsigned char *repl = lookup_replace_object(sha1);
-	void *buffer = read_sha1_file(sha1, &type, &size);
+	void *buffer;
+	struct object *obj;
 
+	obj = lookup_object(sha1);
+	if (obj && obj->parsed)
+		return obj;
+
+	buffer = read_sha1_file(sha1, &type, &size);
 	if (buffer) {
-		struct object *obj;
 		if (check_sha1_signature(repl, buffer, size, typename(type)) < 0) {
 			free(buffer);
 			error("sha1 mismatch %s\n", sha1_to_hex(repl));